6.Benign Lesions of the Jaw Bones

Group 26

Types of Lesions

• Tumors affecting the Jaw Bones, which can be

broadly classified into

• Benign - odontogenic Tumors from epithelial,

mesenchymal and ectomesenchymal origin

• Benign - non - odontogenic Tumors from

Mesenchymal Origin

• Cysts of the Jaws

General information

These lesions can vary greatly in size and

severity, and the growths are usually

noncancerous (benign), but they can be

aggressive and invade the surrounding bone and

tissue and may displace teeth.

- Non‐odontogenic tumors include connective‐tissue tumors,

vascular lesions, reactive lesions, and neurogenic tumors.

The clinical presentation and treatment of these lesions vary.

- Osteomas are benign tumors of bone. They are commonly

found within the skull, jaws, and sinuses. These lesions are

typically present as an asymptomatic mass, which can

produce asymmetry of the jaw bones.

- Odontogenic tumors arise from structures involved with

tooth formation.

- Many odontogenic tumors are true benign neoplasms,

whereas others are extremely aggressive, locally destructive

lesions.

Neoplasms from Epithelial

and Mesenchymal Origin

• Ectodermal (Epithelium) from -

• Dental lamina + Epithelial Rests of Serres

• Enamel Organ + Reduced enamel epithelium

• Epithelial Hertwig´s root sheath (Epithelial

Rests of Malassez)

Neoplasms from Epithelial

and Mesenchymal Origin

• Mesenchymal from -

• Dental Papilla

• Dental Sac

Classification

• Benign - odontogenic Tumors from

Epithelial origin:

• (I).Adamantinoma (Ameloblastoma)

• (II).Squamous odontogenic tumor

• (III).Calcifying epithelial odontogenic tumor

(Pindborg´s Tumor)

• (IV).Clear cell odontogenic Tumor

Classification

• Benign - odontogenic Tumors from

Mesenchymal Origin

• (I).Odontogenic fibroma

• (II).Myxoma / odontogenic myxofibroma

• (IV).Cementoma (True Cementoblastoma)

• (V).Dentinoma

Classification

• Benign - odontogenic - Tumors from

Ectodermal Origin

• Enameloma

Classification

• Benign - odontogenic Tumors from Mixed

(Ectomesenchymal) origin

• (I).Odontoma (Complex, Compound)

• (II).Ameloblastofibroma

• (III).Ameloblastic fibrodentinoma and ameloblastic

fibroodontoma

• (IV).Odontoameloblastoma

• (V).Adenomatoid Odontogenic Tumor

Classification

• Benign - non - odontogenic Tumors from

Mesenchymal origin - Connective Tissue origin

• Fibrous tissue - fibroma

• Fat tissue - lipoma

• Bone tissue - osteoma

(Peripheral - Periosteal Osteoma,Central - Endosteal

Osteoma - Enostoses, located in medullary bone )

• Cartilage tissue - chondroma

Classification

• Benign - non - odontogenic Tumors from

Muscular Tissue

• Striated muscular tissue - Rhabdomyoma

• Smooth muscular tissue - Leyomyoma

• Note, these are just benign mesenchymal

tumors but not affecting the Jaws, its an

additional information.

Classification

• Benign - non - odontogenic Tumors from

Vascular endothelium

• Blood vessels tissue - Haemangioma

• Lymph endothelium tissue - Lymphangioma

Classification

• Benign - non- odontogenic Tumors from

peripheral nerves

• Neurinoma

• Schwann´s cell Tumor

• Neurofibroma

Clinical Features

• Ameloblastoma - Odontogenic Epithelium

• Most common benign tumor from epithelial origin, which

can affect jaw bones with clinical significance

• local aggressive growth

• True Neoplasm

• local invasive growth - Mandibular angle most commonly

affected, then the Ramus mandibulae, and the posterior

part of the Corpus mandibulae in 70% of the cases.

Features

• Can be

• Unicystic

• Multicystic

• Peripheral

• Luminal, Intraluminal and Mural

Histologic types

• Basal cell type

• Follicular cell type - most aggressive

• Acanthomatous

• Plexiform

• Desmoplastic

Clinical features

• Early stages - asymptomatic

• Slow growing, painless, hard, non-tender, ovoid swelling

• Paraesthesia

• Exophtalmus - Unilateral

• Pathological fracture

• Exapansion of the cortical plate

• Honey comb appearance

• Resorption of root

Diagnostic Method

• Recently diagnosed by:

• MRI

• CT

• 1cm - Unicystic

• 1.5cm - Multicystic

• The biological character gives the answer for treatment

• Peripheral ameloblastoma seen in younger patients and most commonly

in the premolar region

• Honneycomb appearance - Multcolar radiolucency, Well defined

Differential Diagnosis

• Odontogenic Keratocyst - initial Diagnosis is

confirmed by histopathological examination -

Aspirational Biopsy

• Central Giant-Cell Granuloma

• Herobism - Eosinophilic granuloma, which

mimics odontogenic tumor

Treatment

• Curettage - should never be considered,

because of higher recurrence-rate, especially in

multi cystic forms

• Conservative local resection - low recurrence-

rate

• Tumor confined to the Maxilla with Orbital floor

involvement - Treatment of Choice is

Maxillectomy

Adenomatoid odontogenic Tumor

- Pseudo - Ameloblastoma

• Originating from reduced enamel Epithelium

• Not aggressive

• Slow growing

• Not invasive

• Two-third Tumor - Occurs in maxilla, canine, impacted teeth

• Cortical Plate expansion, especially vestibular thinner

• Treatment includes Enucleation

Forms

• 3 Variants are observed:

• Follicular,

• Extrafollicular

• Peripheral - Extra-osseus

Squamous odontogenic

Tumor

• Involving the Anterior Alveolar processes

• Mimic parodontal cyst

Mesenchymal

• Ameloblastic fibroma - 70% mandible involvement, in the posterior region

• Ameloblastic fibro-odontoma

• Odontoma - Complex - Represented in a disoriented pattern, it has no

clinical significance

• Odontogenic Myxoma - Honeycomb appearance involving the alveolar

process

• Cementoblastoma - Tumor of connective tissue - opaque rounded mass

with thin Radiolucent margins

• Biopsy - Aspirational Biopsy/ Incisional Biopsy/ Exfoliative cytology

• Treatment - Enucleation with peripheral Osteotomy

Cysts of The Jaws

• Cysts of the Jaws -

• A. Epithelial-linded origin

• (I).Developmental origin -

• a.Odontogenic - Gingival cyst of infants, Odontogenic keratocyst, dentigerous cyst,

eruption cyst, developmental lateral periodontal cyst, botryoid odontogenic cyst,

glandular odontogenic cyst, calcifying odontogenic cyst

• b.Non - odontogenic - Midpalatal raphé cyst of infants, nasopalatine duct cyst,

nasolabial cyst

• (II).Inflammatory origin - Radicular Cyst, apical and lateral, Residular cyst,

Paradental cyst and juvenile paradental cyst, Inflammatory collateral cyst

• B. Non-epthelial-lined cyst - Solitary bone cyst, Aneurysm bone cyst

General Clinical Features

• Often asymptomatic, cysts are usually an

incidental finding on imaging taken for another

purpose

• They are generally benign, slow and expansively-

growing and may reach large sizes before they

give rise to symptoms or signs

• Symptoms include: swelling, displacement or

loosening of teeth - depending on the site of cyst

location, pain - if infected or if the jaw fractures

pathologically

Clinical Features

• The most important clinical sign initially is the expansion of

bone - smooth bony hard lump with normal mucosa. As

bone thins, it may crackle on palpation like an egg shell,

giving rise to the clinical sign of `eggshell cracking`

• The cyst may resorb bone and show as a bluish fluctuant

swelling, then the sign of fluctuance may be elicited by

palpating with fingertips on each side of the swelling in two

positions at right angles to each other.

• If the cyst becomes infected, the clinical presentation may

be that of an abscess, the underlying cystic lesion only

becoming apparent on radiographic examination.

Radiological Signs

• Classically, cysts appear as well-defined round or ovoid radiolucencies, surrounded by a well-

defined margin

• Margins. Peripheral cortication (radio-opaque margin) is usual. ´Scalloped`margins are seen in larger

lesions, particularly keratocysts. Infection of a cyst tends to cause loss of the well-defined margin

• Shape. Most cysts grow by hydrostatic mechanisms, resulting in the round shape. Odontogenic

keratocysts and solitary cysts do not grow in this manner and have a tendency to grow through

medullary bone rather than to expand the jaw.

• Locularity. The locularity (multiple cavities) is seen occasionally in odontogenic keratocysts. However,

larger cysts of most types may have a multilocular appearance because of ridges in the bony wall.

• Effect upon adjacent structures.Where a lesion abuts another structure, such as a tooth or the inferior

mandibular canal, it may cause displacement. Roots of teeth may be resorbed. When a cyst reaches

a certain size, the cortex of the bone often becomes thinned and expanded. In posterior maxillary

lesions the astral floor may be raised. Perforation of the cortical plates may be recognized as a

localized area of greater radiolucency overlying the lesion.

Diagnosis

• Most Cysts are discovered on radiography. In the mandible they, by definition, arise above the inferior alveolar canal.

• MRI, MDCT or CBCT can help distinguish solid and cystic lesions.

• Other investigations may include pulp vitality testing, aspiration and analysis of cystic fluids, and histopathology. Microscopic

examination of the cyst wall provides the clear diagnosis that is important to the management of the lesions, and submission of all

excised tissue (including fragments scraped off from the wall of the jaw cyst and peripheral tissues curetted at the time of dental

extraction or apiectomy) for histopathologic examination is strongly urged.

• Thank You for Your Trust - Group 26

• Omid Araghchi

• Regina Boxhorn

• Giulia Benedetti

• Linda Tariq

• Arwin Shakibapour

• Alessandro Mollica Collela

• Andrea Casarella

• Franceso Casarella, Antonio Rizzo